CTB Gels Might Be What's Missing From Your Outdoor Portraits

I’m a huge advocate of gelling your flash. It’s one of those things that a lot of photographers just discovering off-camera lighting will often fly right past without much thought (I know I did). Even after you get that first stack or plastic bag of gels, knowing how to apply them can be a little intimidating. Enter Michigan-based Photographer Rob Hall’s expert instructions on how you should or could be using your color temperature blue (CTB) gels.

In a recent video on his YouTube channel, Hall gives a thoughtful introduction to color temperature and how gelling a flash blue can benefit your photography when shooting in the shade. I know that I’m guilty of thinking about color temperature orange gels first whenever I start modifying light. Rob’s blue gel tutorial gave me simple, direct motivation to put my CTB gels at the front of my mind the next time I’m using a flash outside. “Given the adjustment power of a raw file, white balance can be easy to ignore,” Hall told Fstoppers. “While a CTO is common for balancing flash to tungsten lighting, the use of CTB on location is rare.”

He’s so right. I was shocked by how many comments on Hall’s video seemed to reveal the neglect that the CTB gel is getting in the photography community. It just goes to show you that you can never absorb too much information about the things that fundamentally drive imaging, even if you think you’ve mastered it all. “YouTube comments show this is 'revolutionary' to some experienced photographers,” Hall said. “Overall, it's an underused tool that won't fill the gear bag. Being aware of the control and effects that gels provide is increasingly important as our industry continues to value working in unique locations.”

Are you using CTB gels regularly to balance color or for effect? Let us know below.

Adam Sparkes's picture

Adam is the Assistant Director of Photography at Central Michigan University. He has been pushing a button for a living since 2009 and for that entire time constantly finds himself correcting people who pronounce it "fur-tographer".

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I use CTB quite a bit for sunset portraits.

Great tip! Thanks for sharing Robert's video!

What would auto WB do in this situation?

quit, and start looking for new job

Gabe, there's no telling what results you'll get if you leave it up to your camera to decide and it may even change from shot to shot. By setting your camera's WB you dictate the end result.

The key here is to understand why one would gel its lights in the first place. You do that to balance or unbalance light colors relatively to the other lights.

To make it simple, just remember this list from more orange to more blue.
- candle light = very orange = 2800K
- tungsten light = orange = 3200K
- fluorescent light = about yellow/orange 4000K (but often "polluted" with tints of green)
- sunny light (and flash light) = the DEFAULT neutral = white = 5600K
- cloudy light = blueish = 6500 K
- shadow light = very blue = 7500 K or higher

Then what ever setting you set your white balance to changes your neutral to that setting. The rest being shifted relatively.

If you set to tungsten, tungsten will be white and sunny light will appear even bluer than it is because relatively to tungsten, it's always more blue.
If you set to shadow, shadow will be white and sunny light will appear more orange than it is because relatively to shadow, it's always more orange.

The latter case it what we have in the video above. CTB is placed on flash lights so they have the same color as shadow light. That color is picked as neutral. Therefore sun light (which is more orange than shadow) now appears orange.

Smoking a cig out there huh?